From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6F49427A907 for ; Wed, 9 Sep 2026 05:45:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788932753; cv=none; b=cJiIpn83TpOp1JcByrxK0sVpqQjDxWRVxM+Cgk0J/UFe1y+A22tG/UPkGqJhBcLlgF55jlo88C7azx9R5bLzDK+FtGL55XsD/h1w8WMmMS630H3zrHdJdqlqmsgqq19DV5DsD9jOu5i2JqVwLxy6LEpy5hmZl8qlQNYc5IIDE4w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788932753; c=relaxed/simple; bh=rAxxa3oVztbKrlVg4k8ZeSMq5sU4NZKxrJQ+/YIe28o=; h=From:Subject:To:Cc:In-Reply-To:References:Content-Type:Date: Message-Id; b=pwtA13uWqGXAoePrbDdWoOljvLVZQmWXqYqLxk4GhUnDE60I7REzADyzHw7QJahubOaag0o16myMNEgFF/RKIKZbgvT7tV7FiOzLsM84SVuzxN1Avc0+XNgDNtDyH/Y9m5JgAZJfqo25wFAWDHtm35K+IfrFHbk2ZfuGYRTbTmA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=XOEKMMvW; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="XOEKMMvW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DCB841F00A3A; Wed, 9 Sep 2026 05:45:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788932752; bh=xne6g00QTbEyIHsqtXK/41YYJU40rvuyxMSsgl1Auzw=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=XOEKMMvWkuw9gtZHvBdnWnwQNzbv+57w7Vh82bV7bkHg6TlvSkM9pt1JMvMZLcxTD 4A98tuaFQjl2ptsFCsLREw5u7uiUwbQudOSE6oM9U8Jjs04PIzZYNtASwILlLH2Hgt MV4JLr8L+CeW03LYyauXdn9mDqVfTf6eAgiQjZlJUgsAhZmBTnkaZzlsQf3YLeNtBv Rg379L+8GAYKhmb3cHvPAw2hHSEcpGZ/8Ci4pPaTzIl5h0vgzKSc/qf+xBNQN+Hk9S XZcWXzrEsd6lxkwU9b5yNa9Ztcs1xdKhb1UwF5UFtJv7flkN0Nyc417I1QcU/188qs R24EDtT4+LSUw== From: sashiko-bot@kernel.org Subject: Re: [PATCH 6.18.y] mm/damon/paddr: drop last same folio access check reuse optimization Reply-To: sashiko-reviews@lists.linux.dev To: "SJ Park" Cc: damon@lists.linux.dev In-Reply-To: <20260909053834.248582-1-sj@kernel.org> References: <2026090852-ought-makeover-4182@gregkh> <20260909053834.248582-1-sj@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Wed, 09 Sep 2026 05:45:51 +0000 Message-Id: <20260909054551.DCB841F00A3A@smtp.kernel.org> Precedence: bulk X-Mailing-List: damon@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: > It can race when multiple kdamonds are being used. The problem from the > race is doubtful, but the gain from the optimization is also doubtful. > Simply drop the optimization in favor of code simplicity. >=20 > The user impact is doubtfully trivial. After all, this kind of > interference can happen only by intentional user setup. Even if it > happens, it will be rare, and the consequence is degradation of the > best-effort monitoring results. No critical consequences like kernel > panic or memory corruption happen. >=20 > The race was discovered [1] by Sashiko. >=20 > Link: https://lore.kernel.org/20260715031002.108504-5-sj@kernel.org > Link: https://lore.kernel.org/20260621204050.10993-1-sj@kernel.org [1] > Fixes: a28397beb55b ("mm/damon: implement primitives for physical address= space monitoring") > Signed-off-by: SJ Park > Cc: # 5.16.x > Signed-off-by: Andrew Morton > (cherry picked from commit f23f0aa62b2f32c2b12f95959fc4603ef81678b2) > Signed-off-by: SJ Park Sashiko has reviewed this patch and found no issues. It looks great! --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20260909053834.2485= 82-1-sj@kernel.org?part=3D1